New combination antiretroviral therapies have demonstrated unprecedented efficacy yet require strict adherence to complex dosing regimens to inhibit rapid virus replication and the generation of multi-drug resistant strains. This proposal for a COMPETING CONTINUATION OF A FIRST TIME R01 is a randomized, controlled intervention to enhance antiretroviral adherence among inner city outpatients at a public hospital clinic in Seattle, WA. The intervention tests the relative efficacy of a "buddy" system and a pager intervention against standard of care in a 2 X 2 factorial design. Both interventions are practical, relatively inexpensive, do not require extensive training or additional staff, and have the potential for easy and widespread dissemination. Conceptually based in the social support literature and social learning theory and supported by findings from the original buddy project and preliminary studies of the pager intervention, the current project is designed to test the effects of providing affirmational, emotional, spiritual, and informational support to target key groups of mediators known to affect adherence: self-efficacy, negative affective states, substance abuse, knowledge of the medication regimen, and remembering doses. The buddy intervention involves clinic staff nominating adherent patients as "buddies" who undergo a brief training and receive regular supervision thereafter. The buddies provide social support to fellow patients in accordance with a protocol explained and rehearsed in their training. The pager intervention employs two-way pagers that prompt participants with descriptions of doses and special instructions and provide information about the medications. Adherence of 240 patients will be assessed with self-reports, pharmacy refills, 3-day recall telephone interviews at months 2 and 4, and the Medication Event Monitoring System (MEMS). All participants will be administered face-to-face interviews (assessing demographics and other potential moderators, social support, adherence, and the proposed mediators) at baseline, at the end of the 3-month intervention, and at a 3-month follow-up. This study will provide useful data on rates and correlates of adherence in this at-risk population, on various adherence assessment methodologies, and on the efficacy of two interventions with high exportability.